question about R4 dvd format

No, as the USA is NTSC and Australia is PAL. Hard luck.

Most cheap generic DVD players can be made region free by punching in a secret code. If the remote has a button marked N/P or vice versa, that pretty much guarantees it is multi format ready.

Most cheap generic DVD players can be made region free by punching in a secret code. If the remote has a button marked N/P or vice versa, that pretty much guarantees it is multi format ready.

That NP or PN button on the remote just about guarantees that the player will convert PAL to NTSC and vice versa. Multiregion players are virtually always multiformat as well. Go look at the cheapest new or used DVD players, see if the remote has that format button, then Google the model number to find the secret code and the correct sequence to use it. Take a PAL DVD and try the player before you buy. Used DVD players could have problems.

If you can find a working Apex AD500 with the correct ROM, then you've stumbled on a gold mine. I had two of them; as far as region/Macrovision-free machines went it was really a b1tchin' piece of hardware in its day. Now it's come down to finding region-free DVD-ROM drives for PCs.

Lighten Up...

Early generic players like the Apex sometimes had issues dealing with anamorphic PAL DVDs; the movie would play, but the aspect ratio wasn't correct. And, they may not have progressive scan outputs and definitely no HDMI. I picked up a Blu-ray player that could be made region-free for DVDs, and does NTSC-PAL conversion for just $15 at the Salvation Army. That unit does a fine job of upconverting DVDs from any region or format, although lately I've mostly just been ripping them all to mkv and playing them back on the WDTV Live.

There's often better firmware available for DVD and BD computer drives. Also, many DVD drives limit the ripping speed, which is annoying. There's a patcher called MCSE (Media Code Speed Edit) that can be used to fix that.
http://www.rpc1.org/
http://ala42.cdfreaks.com/MCSE/